Good Question! Either can cause illness and eventually be fatal depending on concentrations and the types of mold or bacteria you are exposed to.
Mold typically affects a person over a period of time to where you can develop a sensitivity to a particular mold or molds. Though, there are reactions that are much quicker from a person if the mold spore concentration is extremely high in the air. However, it can also be the bacteria in the air that grow along side mold in damp/wet conditions that is affecting a person.
Bacteria, that is dangerous bacteria, and usually gram-negative bacteria can affect you much quicker in a matter of hours especially from the endotoxins these produce which are potentially fatal. So from a professional and personal standpoint I am more concerned about the dangerous bacteria with the endotoxins than I am about fungi or mold by itself.
Keep in mind that mold under California law is defined as ‘microorganisms or fungi’ which include all living matter at the microscopic level. This means, as mentioned, not just mold or fungi but also dangerous bacteria with endotoxins.
Steve Mullins (i.e. mold detector)
CMC, Certified Microbial Consultant
Moisture and Mold Detection, Inc.